This invention relates to novel indanylidene compounds which effectively absorb ultra violet (UV) radiation and to light screening compositions containing these indanylidene compounds.
Light screening compositions including indanylidene compounds are reportedly disclosed in EP 0823 418 A2. This publication emphasizes cyano-(2,3-dihydroxy-1H-inden-1-ylidene) acetic acid ester compounds. These compounds, however, do not have a sufficient solubility in the media typically employed in cosmetics, in particular in oil and fats. Furthermore, it is desirable that the active ingredient remain on the surface of the skin, rather than prior art compounds that penetrate into or through the skin.
It has now been found that compounds having an indanylidene residue grafted via a linker to a silane, an oligosiloxane- or a polysiloxane moiety overcome the problem of penetration and show improved solubility compared to prior art compounds.
Accordingly, the present invention provides compounds of the general formula I: 
The invention also provides compositions containing these compounds, and methods of using the compounds and the compositions.
The present invention provides compounds of the general formula I: 
wherein
X is O or NH;
R1 is C1-C20 alkyl, C2-C20 alkyl in which at least one methylene group is replaced by oxygen, C3-C20 alkenyl, C3-C20 alkynyl or a group YS;
R2 is C1-C20 alkyl, C2-C20 alkyl in which at least one methylene group is replaced by oxygen, C3-C20 alkenyl, C3-C20 alkynyl or a group YS; or
R1 and R2 may combine on adjacent C-atoms to form a dioxomethylene ring;
R3 is C1-C20 alkyl, C2-C20 alkyl in which at least one methylene group is replaced by oxygen, C3-C20 alkenyl, C3-C20 alkynyl or a group YS;
R4, R5, R6 are each independently H or C1-C20 alkyl;
n is 0, 1 or 2;
Y is a linker group;
S is a silane-, an oligosiloxane- or a polysiloxane-moiety;
with the proviso that at least one of the R1, R2 or R3 residues is YS.
As used herein, the phrase xe2x80x9cC1-C20 alkylxe2x80x9d refers to straight chain or branched saturated hydrocarbon residues with 1-20 carbon atoms, such as for example, methyl, ethyl, propyl, isopropyl, butyl, sec. butyl, isobutyl, pentyl, neopentyl, hexyl, 2-ethyl-hexyl, octyl, and the like.
As used herein, the phrase xe2x80x9cC2-C20 alkyl in which at least one methylene group is replaced by oxygenxe2x80x9d refers to straight chain or branched saturated hydrocarbon residues with up to 19 carbon atoms having at least one group such as xe2x80x94(CH2xe2x80x94O)xe2x80x94,xe2x80x94(CH2xe2x80x94CH2xe2x80x94O)xe2x80x94, xe2x80x94(CH2xe2x80x94CH2xe2x80x94CH2xe2x80x94CH2xe2x80x94O) and the like.
In the present invention, the phrase xe2x80x9cC3-C20 alkenylxe2x80x9d refers to straight chain or branched unsaturated hydrocarbon residues with 3-20 carbon atoms containing a double bond, such as for example, propen-2-yl, propen-3-yl, buten-3-yl, buten-4-yl, penten-4-yl, penten-5-yl, and the like.
As used herein, the phrase xe2x80x9cC3-C20 alkynylxe2x80x9d refers to straight chain or branched unsaturated hydrocarbon residues with 3-20 carbon atoms containing a triple bond such as for example, propargyl and the like.
As used herein, the phrase xe2x80x9clinker groupxe2x80x9d refers to a C3-C12 divalent alkylene or alkenylene chain which links the silane, oligosiloxane or polysiloxane moiety to the UV absorbing chromophoric residue. In the present invention, xe2x80x9cC3-C12 divalent alkylene chainxe2x80x9d includes straight chain or branched saturated hydrocarbon residues, such as for example, 3-propylene, 2-propylene, 2-methyl-3-propylene, 3-butylene, 4-butylene, 4-pentylene, 5-pentylene, 6-hexylene and the like. In the present invention, xe2x80x9cC3-C12 divalent alkenylene chainxe2x80x9d includes unsaturated hydrocarbon residues containing one or multiple double bonds, such as for example, 2-propen-2-ylene, 2-propen-3-ylene, 3-buten-3-ylene 3-buten-4-ylene, 4-penten-4-ylene, 4-penten-5-ylene, (3-methyl)-penta-2,4-dien-4 or 5-ylene, 11-dodecen-11-ylene and the like. Such chains may be interrupted by one or several oxygen atomforming groups such as 2-ethyloxy-eth-2-ylene, 4-butyloxy-eth-2-ylene, 3,6-dioxa-8-octylene and the like. Preferred linker groups in the present invention are: 3-propylene , 4-butylene, 2-propen-2-ylene, 2-propen-3-ylene or 3-buten-4-ylene.
As used herein, the term xe2x80x9csilanexe2x80x9d refers to a group -SiR7R8R9 wherein R7, R8 and R9 are each independently C1-C6 alkyl, C1-C6 alkoxy or phenyl. The xe2x80x9cC1-C6 alkylxe2x80x9d and xe2x80x9cC-C6 alkoxyxe2x80x9d residues may be straight-chain or branched, such as for example, methyl, ethyl, propyl, isopropyl, n-butyl, tert. butyl, thexyl, (1,1,2 dimethylpropyl) and, respectively, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, tert. butoxy, and thexoxy for the C1-C6 alkoxy. Preferred are alkyl-silane groups, such as for example, trimethylsilane, triethylsilane, tripropylsilane, triisopropylsilane, dimethyl tert. butylsilane, dimethyl thexylsilane, triphenylsilane, dimethylphenylsilane, and the like.
As used herein, xe2x80x9coligosiloxanexe2x80x9d refers to groups of the general formulaxe2x80x94SiR10m(OSiR103)n wherein R10 is defined below and m=0, 1 or 2; n=3, 2 or 1, and m+n=3; or groups of the general formula IIa or IIb 
wherein
A is a bond to the linker Y;
R10 is C1-C6 alkyl or phenyl;
r is 1 to 9.
In the present invention, the term xe2x80x9cpolysiloxanexe2x80x9d refers to groups of the general formulae IIIa or IIIb: 
wherein
A is a bond to the linker Y;
R11 is C1-C6 alkyl or phenyl;
s is from 4 to 250;
t is from 5 to 250;
q is from 1 to 30.
In the present invention, the R1 and R2 residues are preferably C1-C6 alkyl, more preferably C1-C4 alkyl, such as for example, methyl, or a group YS. The R3 residue is preferably C1-C6 alkyl, more preferably C1-C4 alkyl, such as for example, ethyl, or a group YS.
The R4 and R5 residues are preferably C1-C6 alkyl, more preferably C1-C4 alkyl, such as for example, methyl.
The R6 residue is preferably C1-C6 alkyl, more preferably C1-C4 alkyl, such as for example, methyl or hydrogen.
The R10 and R11 residues are preferably C1-C6 alkyl, more preferably C1-C4 alkyl, such as for example, methyl.
In the present invention, the value of xe2x80x9cnxe2x80x9d is preferably 0 or 1, xe2x80x9crxe2x80x9d is preferably 1 to 3, xe2x80x9csxe2x80x9d is preferably 5 to 150, xe2x80x9cqxe2x80x9d is preferably 2 to 10, more preferably a statistical mean value of about 4, xe2x80x9ctxe2x80x9d is preferably 5 to 150, more preferably a statistical mean value of about 60.
In the present invention, each R1, R2 or R3 group may be YS. Thus, the silane-, oligosiloxane- or polysiloxane moiety may be linked via Y to the indane ring or to the carboxy or amide group. Preferably the silane-, oligosiloxane- or polysiloxane moiety is linked to the carboxy or amide group (e.g. R3 is YS).
The compounds of formula I may be prepared as follows:
In a first step, compounds of formula Ia 
wherein R1, R2, R4, R5, R6 and n are as defined above are synthesized according to known reactions (see, e.g., F. Camps, Z. Naturforsch., B: Anorg. Chem., Org. Chem. (1984), 39B (12), 1801-5), and Tetrahedron Letters 27, 2941 (1973), which are hereby incorporated by reference as if recited in full herein.
In a second step, indanylidene compounds of the general formulae Ib, Ic and Id 
wherein R1, R2, R4, R5, R6 and n are as defined above and R12 is a C3-C12 divalent alkylene- or alkenylene chain are synthesized according to known reactions such as the Knoevenagel reaction. As stated above the C3-C12 divalent alkylene- or alkenylene chain may be interrupted by one or several oxygen atoms.
An example synthesis of an indanylidene compound of formula Ib is set forth below for a compound wherein R1 and R2 are methyl, n is 1, R4 and R5 are methyl, R6 is hydrogen and X is oxygen. The corresponding compounds wherein R1, R2, R4, R5, R6 and n are as defined above may be prepared accordingly. The details are described in Example 1. 
An example synthesis of an indanylidene compound of formula Ic is set forth below for a compound wherein R2 is methyl, n is 1, R4 and R5 are methyl, R6 is hydrogen and X is oxygen. The corresponding compounds wherein R2, R4, R5, R6 and n are as defined above may be prepared accordingly. The details are described in Examples 11a and 11b. 
An example synthesis of an indanylidene compound of formula Id is set forth below for a compound wherein R1 and R2 are methyl, n is 1, R4 and R5 are methyl, R6 is hydrogen and X is nitrogen. The corresponding compounds wherein R1, R2, R4, R5, R6 and n are as defined above may be prepared accordingly. The details are described in Examples 8a and 8b. 
In a third step the indanylidene compounds of formulae Ib, Ic and Id are linked to the group YS according to known reactions either via a transesterification or a hydrosilation reaction.
An example of a transesterification reaction is set forth below for the reaction between a compound of formula Ib wherein X is oxygen, R1 and R2 are methyl, n is 1, R4 and R5 are methyl, R6 is hydrogen and a compound ZYS, wherein Z is hydroxy, Y is 4-butyl and S is an oligosiloxane of formula IIa wherein R10 is methyl and r is 1. The details of the reaction are described in Example 2. The corresponding compounds of formula I, wherein X is oxygen, e.g. Examples 3-7, may be prepared accordingly. 
In the hydrosilation reaction, compounds of formulae Ic and Id are reacted with a SiH containing oligosiloxane- or a polysiloxane compound corresponding to the oligosiloxane- or polysiloxane residues as defined above.
Two examples for a hydrosilation reaction are set forth below for the reaction between a compound of formula Id and a SiH containing oligosiloxane and a polysiloxane compound, respectively. The details of this reaction are set forth in Examples 8, 9, and 10. The corresponding compounds of the general formula I wherein X is nitrogen and R3 is YS may be prepared accordingly.
a) Hydrosilation according to Example 8 
b) Hydrosilation according to Example 9 
Examples 11 and 12 of the present invention set forth a hydrolisation reaction between a compound of formula Ic and a SiH containing oligosiloxane- and a polysiloxane compound, respectively. Compounds of formula I wherein X is nitrogen and R1 is YS may be prepared accordingly.
The preparation of novel light screening agents, especially of preparations for skin protection and, respectively, sunscreen preparations for everyday cosmetics, includes incorporating a compound of formula I into a cosmetic base typically used for light screening agents. Other conventional UV-A and UV-B filters may also be combined during this incorporation. The combination of UV filters may lead to a synergistic light screening effect. The preparation of such light screening agents is well known to the skilled artisan in this field. In these light screening agents, the amount of compounds of formula I and other known UV-filters is not critical. Suitable amounts are about 0.5 to about 12%.
As used herein, suitable xe2x80x9cUV B filters,xe2x80x9d include those substances having absorption maxima between about 290 and 320 nm. TVB filters include, for example, the following organic compounds, including but not limited to, for example:
p-Aminobenzoic acid derivatives such as, for example, ethyl, propyl, butyl, isobutyl, octyldimethyl, amyldimethyl, ethoxylated ethyl, propoxylated ethylglyceryl or ethylglycosyl p-aminobenzoate and the like;
Acrylates, such as, for example, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate (octocrylene), ethyl 2-cyano-3,3-diphenylacrylate and the like;
Aniline derivatives such as, for example, methyl anilinum methosulfate and the like;
Anthranilic acid derivatives such as, for example, menthyl anthranilate and the like;
Benzophenone derivatives such as, for example, benzophenone-1 to benzophenone-12 and the like.
Camphor derivatives such as, for example, methyl benzylidene camphor, 3-benzylidene camphor, camphor benzalkonium methosulfate, polyacrylamidomethyl benzylidene camphor, sulfo benzylidene camphor, sulfomethylbenzylidene camphor, therephthalidene dicamphor sulfonic acid and the like;
Cinnamate derivatives such as, for example, octyl methoxycinnamate or ethoxyethyl methoxycinnamate, diethanolamine methoxycinnamate, isoamyl methoxycinnamate and the like as well as cinnamic acid derivatives bond to siloxanes;
Gallic acid such as, for example, digalloyl trioleate and the like;
Imidazole derivatives such as, for example, phenyl benzimidazole sulfonic acid and their salts;
Salicylate derivatives such as, for example, isopropylbenzyl, benzyl, butyl, octyl, isooctyl or homomenthyl salicylate and the like;
Triazole derivatives such as, for example, drometriazole, hydroxydibutylphenyl-, hydroxydiamylphenyl-, hydroxyoctylphenyl- or hydroxyphenylbenztriazole and the like;
Triazone derivatives such as, for example, octyl triazone, dioctyl butamidotriazone and the like; and
Pigments such as, for example, microparticulated TiO2.
The formulation may further contain UV A filters such as, for example:
A Dibenzoylmethane derivative, such as, for example, 4-tert. butyl-4xe2x80x2-methoxydibenzoyl-methane and the like;
Pigments such as, for example, microparticulated ZnO.
Triazine compounds as described in EP 0693483 A1, EP 0704437 A2, EP 0704444 A1 and EP 0780382 A1;
Organosiloxane compounds as described in EP 0538431 B1, EP 0709080 A1 and EP 0358584B1; and Malonates such as, for example, those described in EP 895776 A2.
As used herein, the term xe2x80x9cmicroparticulatedxe2x80x9d refers to a particle size from about 5 nm to about 200 nm, preferably from about 15 nm to about 100 nm.
The present invention includes cosmetic bases typically used for light screening compositions. Thus, such cosmetic bases include, for example, creams, lotions, emulsions, salves, gels, solutions, sprays, sticks and milks; see also, Sunscreens, Development, Evaluation and Regulatory Aspects, ed. N. Y. Lowe, N. A. Shaath, Marcel Dekker, Inc. New York and Basel, 1990, which is hereby incorporated by reference as if recited in full herein.
Having regard to their good lipophility, the compounds of formula I may be incorporated into oil-containing and fat-containing cosmetic preparations such as, for example, in cosmetic preparations containing dimethicone.